A city agency that oversees hundreds of millions of dollars worth of construction projects "grossly overstated" the amount it paid certified minority contractors in 2009, according to a report issued Wednesday by the city's top internal watchdog.

The Public Building Commission reported paying $89 million to certified minority-owned businesses two years ago, but a review of actual payments and certifications indicates those payments were overstated by nearly 40 percent, the report concludes.

Inspector General Joseph Ferguson also found that the commission overestimated payments of $16.1 million to certified women-owned businesses by 3 percent. And he alleged that the commission was not complying with its responsibility to allow him to probe all projects involving city money.

In 2009, the commission spent $243.3 million on 15 projects that included the construction of police stations, libraries, schools and fieldhouses.

At the time, the panel was controlled by former Mayor Richard Daley. New Mayor Rahm Emanuel led his first commission meeting Tuesday. A commission spokeswoman said the agency had to review the report before commenting.

Payments to certified minority- and women-owned businesses were overstated because the commission did not thoroughly track actual payments to specific vendors and in some cases included unqualified minority- and women-owned businesses, the report concludes.

City goals call for 25 percent of all contract payments to go to minority firms and 5 percent to go to female firms. Emanuel recently switched oversight of those goals from the Office of Compliance to the Office of Procurement.

City Council Black Caucus Chairman Ald. Howard Brookins Jr., 21st, said he wasn't surprised to learn the minority contractor numbers of the building commission were lower than had been reported. "Minority contractors are consistently telling us the numbers are low" across city government, Brookins said.

He said he is hopeful Emanuel will take the lead on rectifying the situation.

"I believe he will address this, and I'm going to be there in his ear to be sure this is something at the top of his list of things to do," Brookins said.

The commission, set up in 1956 by Mayor Richard J. Daley, oversees building construction for the city, Cook County, Chicago Public Schools, the Chicago Park District and other agencies.